Tanghwa Kungfu Malatang Seongsu is a malatang restaurant in Seongsu where you pick the ingredients you want. You choose a spice level and a peanut sauce flavor. After ordering you get a number ticket and sit down, then take your food yourself when your number is called or have staff bring it to your table. At weekday lunch there can be a short wait at 12:30, and seats open up around 1.